Who are you referring to as 'he'? There was someone claiming to have an 8hp75 in their car with no adapter, swearing up and down, but never backed it up, is that who you're referring to?
Ah, I didn't know the 6r80 solenoids were controlled externally, that would make it a lot easier. To get trans brake working without an external TCU, probably need to get some wires direct to the solenoids.
My apologies for not being more specific I dont know his name right now, but yes it was the person claiming to have an 8HP75 that bolted straight up no adatper... not an 8HP70 my mistake.
Yes for the trans brake, one way or another youre going to have to wire into the solenoids which would be easier if the TCU was external but I still think its doable in way or another either with bulkhead seal for wires through pan or preferably with unused pin/connector locations on the factory TCU/mechatronic connector.